Addendum to: Undo in region after markers in undo history relocated

* simple.el (primitive-undo): Correction to 2014-03-24 change.

Fixes: debbugs:16818

lisp/ChangeLog

@@ -1,3 +1,7 @@
+2014-03-25  Barry O'Reilly  <gundaetiapo@gmail.com>
+
+	* simple.el (primitive-undo): Correction to 2014-03-24 change.
+
 2014-03-25  Michael Albinus  <michael.albinus@gmx.de>
 
 	* net/tramp.el (tramp-methods, tramp-connection-timeout): Fix docstring.

lisp/simple.el

@@ -2321,9 +2321,10 @@ Return what remains of the list."
            ;; Even though these elements are not expected in the undo
            ;; list, adjust them to be conservative for the 24.4
            ;; release.  (Bug#16818)
-           (set-marker marker
-                       (- marker offset)
-                       (marker-buffer marker)))
+           (when (marker-buffer marker)
+             (set-marker marker
+                         (- marker offset)
+                         (marker-buffer marker))))
           (_ (error "Unrecognized entry in undo list %S" next))))
       (setq arg (1- arg)))
     ;; Make sure an apply entry produces at least one undo entry,